The car in question is a 1987 760GLE with the auto trans. When I first start it in the morning, for the first 3 or 4 seconds when warm, it acts normally. After that, while warming up, it will idle fine, but as soon as you attempt to push the gas, it refuses to go above 1500 RPM and just sits there popping and missing. It usually does this until its fully warmed up, but sometimes you need to shut it off and turn it back on before it acts as described below.

Once its warmed up, about 0-20% throttle seems to work fine, 20%-95% all feels like the same amount of power as 20% but with some occasional misfires and the transmission kicking down a gear past a certain point (but still no more power). However, if you go full-throttle, it'll kick down to the lowest gear and feel like it has the normal amount of power. If you don't go full-throttle, the car has a terminal velocity of about 50 mph, which makes highway driving a real PITA.

I've replaced the plugs, distributor, pulled out all of the engine wiring and re-did the harness so nothing would be shorting (i know the harness is correct b/c it worked fine after I did that), and have touched up the wiring in other parts of the car as well. I'm very confused about what this could be. EGR maybe? bad timing maybe? Crank angle sensor? (although it seemed to be fine around the time I did the harness) Help!

Thanks a lot!